Walmart on Thursday unveiled a new concierge shopping service enabling customers to get quick deliveries and advice from a personal assistant, going upscale in the retail giant's battle with Amazon.

The new $50 per month service called Jetblack is launching in New York, offering "curated shopping recommendations" using both artificial intelligence and professional assistants.

The new subscription service ramps up competition with Amazon, which gives customers a variety of benefits and delivery options through its Prime subscription membership.

The new Walmart service comes from its recently acquired Jet.com online platform and its technology incubator known as Store No. 8.

Jetblack will let customer text requests for items such as birthday gifts.

Operating in the New York boroughs of Manhattan and Brooklyn, it offers same-day and next-day deliveries from Walmart, Jet.com and its retail partners, which are expected to include local boutiques and luxury retailers.

It will be led by Jenny Fleiss, co-founder of the retail fashion rental service Rent the Runway, who joined Walmart last year.

The website offered few details, offering customers an opportunity to join a waiting list.

"We are thrilled to introduce Jetblack to the world today," said Fleiss in a statement.

"Consumers are looking for more efficient ways to shop for themselves and their families without having to compromise on product quality. With Jetblack, we have created an entirely new concept that enables consumers to get exactly what they need through the convenience of text messaging and the freedom of a nearly unlimited product catalogue."

Jet.com founder Marc Lore said the new service using "conversational" commerce "will have a profound impact on how customers may shop five years from now."

Walmart and other retailers have been scrambling in the face of Amazon's push into various sectors including groceries, with more than 100 million Prime subscribers.

Eye-watering, throat-scratching air pollution is a major driver of big city blues in China, according to a study published Monday that matched social network chatter with fine-particle pollution levels.